Why Isn't My Filter Filtering? >:(

[kmerkel]

Making a long backstory short, filtration has been an issue since we opened the pool for the first time four seasons ago. Some of the equipment was inherited from the previous owners of the house, and almost all of the functional parts have been replaced since then, including the MPV, sand, and just this spring, the standpipe with laterals.

This season started out beautifully, with water clearer than it ever had been (so much so that friends were giving compliments!), but now it's reverted back to form, with red/brown sediment accumulating which isn't caught by the filter during vacuuming; the MPV may as well be in bypass. I did a deep clean on the filter today but that did squat to improve filtration.

What am I doing wrong or have I overlooked?? I really want to fix it once in for all, especially now that I know it can work after seeing how well it did in the spring. I just don't know what changed, or why. I also keep the chemistry pretty well in check and maintain chlorine on a daily basis.

I look forward to the insights.

Thanks in advance,
Kyle

 

[Bperry]

Making a long backstory short, filtration has been an issue since we opened the pool for the first time four seasons ago. Some of the equipment was inherited from the previous owners of the house, and almost all of the functional parts have been replaced since then, including the MPV, sand, and just this spring, the standpipe with laterals.

This season started out beautifully, with water clearer than it ever had been (so much so that friends were giving compliments!), but now it's reverted back to form, with red/brown sediment accumulating which isn't caught by the filter during vacuuming; the MPV may as well be in bypass. I did a deep clean on the filter today but that did squat to improve filtration.

What am I doing wrong or have I overlooked?? I really want to fix it once in for all, especially now that I know it can work after seeing how well it did in the spring. I just don't know what changed, or why. I also keep the chemistry pretty well in check and maintain chlorine on a daily basis.

I look forward to the insights.

Thanks in advance,
Kyle

Got any pictures of the equipment along with some water test results? Are you sure it’s dirt?

 

[kmerkel]

I'm presuming it's some kind of airborne contaminant/dirt that's precipitating into the pool but I'm honestly not sure how to test for what it actually is. To my eyes it does not have the same appearance as algae.

The chlorine has not dropped to 0 all season, including the last few weeks. Test results as of this afternoon:
FC: 2.5
CC: 0
TA: 130
PH: 7.6
CYA: 40 (as of two weeks ago)
I have not been tracking CH since there's nothing I can do about it. Also, I added chlorine afterwards so actual FC is probably closer to 5 now.

I can definitely get equipment pictures but my setup is in my signature and I don't know what value they would bring, unless there is something specific you would like to see?

 

[Bperry]

I'm presuming it's some kind of airborne contaminant/dirt that's precipitating into the pool but I'm honestly not sure how to test for what it actually is. To my eyes it does not have the same appearance as algae.

The chlorine has not dropped to 0 all season, including the last few weeks. Test results as of this afternoon:
FC: 2.5
CC: 0
TA: 130
PH: 7.6
CYA: 40 (as of two weeks ago)
I have not been tracking CH since there's nothing I can do about it. Also, I added chlorine afterwards so actual FC is probably closer to 5 now.

I can definitely get equipment pictures but my setup is in my signature and I don't know what value they would bring, unless there is something specific you would like to see?

FC of only 2.5 is below the minimum with that CYA level. You may be on the edge of an algae event if it gets that low frequently. You be wise to keep it up near 7ppm so that when it drops during the day the minimum is always over 3ppm.

 

[kmerkel]

Yikes, OK. I'm pretty sure I've been keeping it above 3 most of the time, but once I figured out how much of a chlorine dose it needed every day I only checked the FC about once a week, so there may have been some variation towards the low end that went under the radar. I also figured a CC of 0 was a good sign that there were no organics consuming the chlorine.

I started a SLAM tonight and gave the whole pool a good brushing, so we'll see if things improve.

Is there a way to determine exactly what this dirt is? We had a fairly dry start to the summer here, and only when the rains came in the second half did the water cleanliness start to suffer. Mostly I'm concerned that the filter isn't effective down to the micron level it should be, which would be extremely frustrating since every functional part in the filter is no more than a few seasons old.

 

[Bperry]

Yikes, OK. I'm pretty sure I've been keeping it above 3 most of the time, but once I figured out how much of a chlorine dose it needed every day I only checked the FC about once a week, so there may have been some variation towards the low end that went under the radar. I also figured a CC of 0 was a good sign that there were no organics consuming the chlorine.

I started a SLAM tonight and gave the whole pool a good brushing, so we'll see if things improve.

Is there a way to determine exactly what this dirt is? We had a fairly dry start to the summer here, and only when the rains came in the second half did the water cleanliness start to suffer. Mostly I'm concerned that the filter isn't effective down to the micron level it should be, which would be extremely frustrating since every functional part in the filter is no more than a few seasons old.

Your filter is likely not the problem. I have a sand filter with tons of junk getting blown into the pool and it stays crystal clear as long as you maintain the chlorine. You need to make sure it NEVER drops below 3ppm even for a day and bringing it back up to 7ppm every night. I’d personally make the number 4ppm for my minimum.

 

[Mdragger88]

An Overnight Chlorine Loss Test will help confirm organics which I suspect based on your poolmath logs, u have dipped below minimum for your cya several times. FC/CYA Levels
Minimum is the no no zone not the target
In the future (after the SLAM Process is complete) be sure to dose to the high target for your cya or a scootch higher so you don’t broach minimum & risk algae again.
Be sure to get an accurate cya reading so u can chlorinate accordingly.

For a successful SLAM Process
you need to continue to MAINTAIN Slam level fc for your cya until you meet ALL 3 end of slam criteria- the more often u test & replenish fc the faster things will improve.

You are done when:

CC is 0.5 or lower;
You pass an Overnight Chlorine Loss Test
AND
the water is clear.
(Crystal Clear w/no algae dead or alive)

*Check & scrub every nook & cranny where algae may hide (light niches, steps, drain covers, ladder handrails, skimmer throats/weirs, etc.)
*Run slam level water through all water features & lines for at least a couple hours a day during the SLAM Process.
*Brush & or vac daily (this breaks up biofilms that algae uses to protect itself from chlorine)
*Backwash/clean filter when pressure rises 25%over clean pressure.

 

[kmerkel]

Thanks for the input. I am all too familiar with the SLAM process, thanks to what it took to open the pool the first season we lived here...

I'll keep the chlorine up and see how things go.

On a side note about the filter, there's some variance in the clean pressure. I've seen it as low as 8 and high as 11psi, even after a backwash. Guess I'll just use whatever it's decided to be now as a baseline.

 

[kmerkel]

Update: It's looking great now. The effluent from the filter backwash today was more of an olive green color; maybe the silt/sediment just looked brown against the medium blue hue of the pool liner? Either way, lesson learned! Thanks again for steering me straight.